sunxi: Fix arm64 fdtfile variable

Currently $fdtfile is constructed from CONFIG_DEFAULT_TREE, containing
the filename. However on arm64 that file is located in an allwinner
subdirectory.

To avoid the need for users/distros symlinking the .dtb files, prepend
the vendor directory for ARM64.

This aligns Pine64 with other boards such as Raspberry Pi 3.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Jagan Teki <jagan@openedev.com>

include/configs/sunxi-common.h

@@ -497,11 +497,17 @@ extern int soft_i2c_gpio_scl;
 	CONSOLE_STDIN_SETTINGS \
 	CONSOLE_STDOUT_SETTINGS
 
+#ifdef CONFIG_ARM64
+#define FDTFILE "allwinner/" CONFIG_DEFAULT_DEVICE_TREE ".dtb"
+#else
+#define FDTFILE CONFIG_DEFAULT_DEVICE_TREE ".dtb"
+#endif
+
 #define CONFIG_EXTRA_ENV_SETTINGS \
 	CONSOLE_ENV_SETTINGS \
 	MEM_LAYOUT_ENV_SETTINGS \
 	DFU_ALT_INFO_RAM \
-	"fdtfile=" CONFIG_DEFAULT_DEVICE_TREE ".dtb\0" \
+	"fdtfile=" FDTFILE "\0" \
 	"console=ttyS0,115200\0" \
 	SUNXI_MTDIDS_DEFAULT \
 	SUNXI_MTDPARTS_DEFAULT \